ASPxCheckBox - The server-side CheckedChanged event doesn't fire in Navbar

Hello,  I've defined two checkboxes in the NavBar template but it is not responding to the onCheckedChanged event.  What am I missing?

Thank you
Kim

<div class="row">
        <div class="col-md-3">
            <h2>Filter</h2>
            <p>
                Filter by Sponsor, RFA or Opportunity Name.
            </p>
            <p>
                <a class="btn btn-default" href="http://go.microsoft.com/fwlink/?LinkId=301949">Learn more »</a>
            </p>
            <dx:ASPxNavBar ID="ASPxNavBar1" runat="server">
            <Groups>
                <dx:NavBarGroup Name="Sponsor" Text="Sponsor">
                    <ContentTemplate>
                        <dx:ASPxCheckBox ID="chkboxAdministration" runat="server" Text="Administration" CheckState="Unchecked" ClientInstanceName="chkboxAdministration" OnCheckedChanged="chkboxStatus_CheckedChanged">
                        </dx:ASPxCheckBox>
                        <dx:ASPxCheckBox ID="chkboxProvost" runat="server" ClientInstanceName="chkboxProvost" OnCheckedChanged="chkboxProvost_CheckedChanged" Text="Provost">
                        </dx:ASPxCheckBox>
                    </ContentTemplate>
                </dx:NavBarGroup>
            </Groups>
        </dx:ASPxNavBar>
        </div>
        <div class="col-md-9">
            <h2>Getting started</h2>
            <p>
                Limited Sumission Database.
            </p>
            <dx:ASPxGridView ID="grid" runat="server" ClientInstanceName="grid" OnCustomCallback="grid_CustomCallback"></dx:ASPxGridView>
        </div>